Japanese H-IIA Rocket successfully launches IGS Radar Satellite

February 1, 2015

A Japanese H-IIA rocket blasted off from the Tanegashima Space Center at 1:21 UTC on Sunday, embarking on a semi-secret mission to deliver the IGS Radar Spare satellite to orbit for as part of the classified Information Gathering Satellite Program. As Japan’s primary reconnaissance satellites, the optical and radar satellites of the IGS fleet are regularly replaced to ensure a continuity in global surveillance data. According to the Japan Aerospace Exploration Agency, H-IIA successfully delivered the IGS satellite to its target orbit which is not being disclosed to the public.

The IGS program was initiated back in 1998 when North Korea conducted a test of a ballistic missile that overflew Japanese territory. In response to this test and the growing threat represented by North Korea, the Japanese government identified the need of an independent capability to monitor activity on foreign territories with special focus on military activity that could indicate an imminent threat. The first pair of IGS satellites launched in 2003 and consisted of an optical imaging spacecraft and a satellite carrying a radar payload for all-weather and nighttime imaging.

Over the years, several generations of satellites were launched with improvements in the ground resolution reached by the optical and radar instruments. The Radar Spare Satellite was apparently ordered as a spare for the first two IGS radar satellites launched in 2003 and 2007 – now being launched to replace one of the aging IGS satellites, possibly the IGS 5B satellite launched in 2009.

Coming back from a weather related delay earlier in the week, teams initiated the H-IIA countdown that started with the rollout of the 53-meter tall rocket that emerged from its assembly building at 11 UTC on Saturday. The 500-meter trip over to the launch pad took just under 30 minutes to complete as H-IIA rolled atop its Mobile Launch Platform was carefully centered on its launch pad. Arriving at the pad, H-IIA started countdown operations at one of the world’s most beautiful launch sites located on Tanegashima Island south of Kyushu, Japan’s southernmost main island.

The conclusion of the rollout marked the start of several hours of hands-on work for technicians who connected the launch vehicle to the various propellant, pressurant and purge umbilicals and also put electrical and data connections in place. Later, the launcher and pad were closed out and workers departed the launch area as the 400-meter safety zone came into effect when H-IIA was powered up to begin a detailed set of pre-launch checkouts.

The launch vehicle underwent communications checks via its S-Band and C-Band systems, the Flight Termination System was tested and the Flight Control System was initialized. The flight software was loaded into the computers of the vehicle and the control system was thoroughly checked. Engine slews on the first and second stage engines were performed and teams completed the final steps to start propellant loading.

*File Image* - Photo: JAXA

The safety zone was extended to 3,000 meters when propellant loading operations got underway at X-7 hours and 45 minutes. The first step of propellant loading was the pressurization and chilldown of the Liquid Oxygen and Liquid Hydrogen ground systems, transfer lines and H-IIA tanks on both stages. Once chilldown was complete, the two stages of the launcher were loaded with –183°C LOX and –252°C LH2 – the first stage received about 100 metric tons of cryogenics while the second stage was filled with 16,600kg of propellants.

Propellant loading wrapped up after about three hours with all tanks entering a stable replenish that continuously topped the tanks off at flight level until very late in the countdown. While propellants were being replenished, the various systems of the launcher were put through another round of testing including a repetition of C- and S-Band communication checks, testing of the Flight Control System, verifications of the Flight Termination System and checkouts of various ground systems. After final testing, the countdown entered a quiet period as it approached its final hour.

Terminal Countdown started at X-60 minutes. Entering the final hour of the countdown, teams started the final reconfigurations of the launcher for the Automated Countdown Sequence.

A revised version of the Flight Software was loaded into the computers of H-IIA based on measurements of winds aloft to ensure the launcher would remain on its planned flight trajectory in the given conditions. Weather on Tanegashima Island was favorable for launch, despite a low-hanging cloud layer with calm winds on the ground, moderate temperatures and no precipitation.

The IGS satellite made its transfer to internal power as clocks ticked down. Placed in its launch mode, the satellite was ready for its trip into orbit and teams made the final checks of all launch support stations and the local range. All stations reported a GO for launch as all systems were ready for the automated countdown and the launch corridor was verified clear.

With the opening of the launch window programmed into all sequencers on the ground and the launch vehicle, clocks started ticking at X-4 minutes and 30 seconds marking the start of the Automated Countdown Sequence. Throughout those final countdown minutes, computers choreographed the events of the countdown and monitored all vehicle parameters ready to trigger an abort in case of problems during the countdown.

The first step of the Auto Sequence was the pressurization of the first stage after its propellant ground feed was cut at X-4 minutes and 20 seconds. Pressurization of the first stage took two minutes to complete. At X-3 minutes, the H-IIA launcher transferred from ground power supply to internal power. The Flight Termination System was switched to internal battery as part of a separate procedure.

One minute before liftoff, thousands of Kilograms of water were being poured over the launch platform to suppress the acoustic loads at booster ignition and liftoff. Ordnances aboard the launcher were armed at X-30 and the Guidance System switched to Flight Mode at X-18 seconds. At X-11.5 seconds, the sparklers underneath the LE-7A Main Engine of the Core Stage ignited to burn off any residual Hydrogen that may be released during the Ignition Sequence.

Ignition sequence start was commanded at X-5.2 Seconds and the fuel and oxidizer valves of the main engine were opened and its turbopumps started spinning to flight speed. Engine ignition was carefully monitored by computers to ensure LE-7A reached its full liftoff thrust of 109,300 Kilograms.

When clocks hit zero, the twin Solid Rocket Boosters ignited and H-IIA blasted off with a total thrust around 575 metric tons, making for a quick initial vertical climb before the pitch and roll maneuver was started to allow H-IIA to get aligned with is precise ascent path. No official broadcast of this launch was provided by either JAXA or MHI, but spectators at the visitors site streamed the launch live on the Internet showing the initial stages of the mission as H-IIA quickly vanished in the low cloud ceiling over the launch site.

Although no information on the mission’s launch profile were released, the target orbit and approximate ascent profile can be deduced from previous IGS launches atop H-IIA. IGS operate from a polar orbit at an inclination of 98 degrees which can not be reached directly from Japan due to inhabited islands in the line-of-sight flight path to the south-west. To avoid rocket debris falling on islands or popular fishing areas, polar launches from Tanegashima require a Dogleg maneuver – that is a guided turn during powered flight. The same requirement exists for missions from India’s Satish Dhawan Space Center from where a polar orbit is only accessible when making a Dogleg to avoid the island of Sri Lanka.

Taking the usual Dogleg Path, H-IIA headed out to the south-east until it was about 100 Kilometers downrange when the guided turn started in the late stages of first stage flight to move the trajectory back to the south-west with the launcher dropping its boosters, first stage and payload fairing in safe zones in the Pacific.

*File Image* - Photo: JAXA

On its way uphill, H-IIA passed Mach 1 after about 75 seconds followed by Maximum Dynamic Pressure as the launcher flew under the power of its liquid-fueled core stage and the twin SRBs that did most of the work at that point in the flight. Burning over 65 metric tons of propellants, each SRB delivered more than 230 metric tons of thrust over the course of its burn. Thrust on the boosters started tailing off after passing the T+100 second-mark and the pressure drop in the boosters was sensed by the onboard instrumentation signaling the burnout of the SRBs that was followed by the separation of the boosters using pyrotechnics and the thrust struts to ensure a clean separation.

*File Image* - Photo: JAXA

With the boosters gone, H-IIA was only powered by its LE-7A engine consuming 260 Kilograms of Liquid Oxygen and Liquid Hydrogen per second delivering 109 tons of thrust. Boosting the stack out of the atmosphere, the first stage continued to stick to the pre-planned trajectory and attitude profile.

After exiting the dense atmosphere, around 130 Kilometers in altitude, H-IIA jettisoned the two halves of its payload fairing, exposing the classified IGS satellite on its way into orbit since aerodynamic forces were no longer a threat to the spacecraft. The first stage continued powered ascent until just after T+6 minutes and 30 seconds when the LE-7A engine was shut down after completing its job. Eight seconds after MECO, the pyrotechnic stage separation system was fired and the 37-meter first stage was pushed away from the second stage.

Around six seconds after staging, the LE-5B engine of the second stage was ignited on the only burn of the flight since the target orbit could be reached with one single firing of the upper stage with a duration of up to eight and a half minutes. Over the course of its burn, the LE-5B engine provided 14,000 Kilograms of thrust consuming nearly 16,600kg of Liquid Oxygen and Liquid Hydrogen. Performance of the vehicle was nominal throughout the burn as H-IIA headed down in the center of the launch corridor – now flying south-west after the Dogleg was completed.

With main engine cutoff occurring about 15 minutes after launch, H-IIA arrived in its target orbit at an altitude of around 500 Kilometers. Spacecraft separation occurred less than 20 minutes after liftoff as the IGS Radar Spare Satellite was dropped off into its target orbit. Confirmation of launch success was provided by JAXA shortly after spacecraft separation occurred.

With this IGS radar satellite entering orbit, an optical IGS satellite is next on the firing line with liftoff currently set for the March/April time frame. The IGS Optical 5 satellite is the first operational satellite of the new generation of spacecraft, a first experimental version of which was launched in January 2013.

Information Gathering Satellites

Information Gathering Satellites are Japan's primary intelligence satellites operated to deliver reconnaissance for the military and intelligence services in the form of optical imagery and high-resolution radar data. IGS satellites carry an optical reconnaissance payload or a Synthetic Aperture Radar for remote sensing. The main purpose of the satellite program is to provide an early warning capability of missile launches. IGS was initiated in 1998 in response to a North Korean missile test that flew over Japan. The first pair of IGS satellites was launched on March 28, 2003 atop an H-IIA 2024 rocket blasting off from the Tanegashima Space Center. IGS 1A was an optical satellite while 1B carried a radar payload. The two spacecraft entered a 486 by 491-Kilometer orbit at an inclination of 97.3 degrees and flew with a separation of about 37 minutes. In March 2007, IGS 1B stopped working, slowly heading forre-entry that occurred on July 26, 2012. IGS 1A has been in a stable orbit until early 2012 when it started dropping, indicating that the spacecraft had depleted its fuel tanks or stopped functioning. It decayed in July 2014. The second IGS launch in November 2003 ended in failure and never arrived in orbit when a Solid Rocket Booster failed to separate from the H-IIA rocket. The IGS 1 and IGS 2 satellites were first generation spacecraft achieving a ground resolution for optical images of 5 meters (color) and about 1 meter (panchromatic). Synthetic Aperture Radar resolution is believed to be better than 3 meters.

IGS 3A was launched by H-IIA in September 2006 and represented the second generation of optical satellites that achieve a resolution of one meter. The satellite operated from an orbit of 480 Kilometers.

The IGS 4 satellite pair launched in February 2007 and included an experimental third generation optical satellite with a ground resolution of better than one meter, and a second generation SAR spacecraft also achieving a resolution of one meter. The satellites were found in an orbit of 481 to 494 Kilometers that they maintained until 2010. In the summer months of 2010, IGS 4B became non-operational for reasons that were not disclosed - it re-entered in November 2013. When satellite 4A stopped functioning is unclear, but orbital data suggests a loss of orbit control between mid-2010 to mid-2011 leading up to re-entry in April 2014.

Photo: JAXA

IGS 5A is another optical satellite of the third generation launched in late 2009 and found in an orbit of about 585 Kilometers. In September 2011, the first fourth generation optical satellite was launched that is believed to achieve image resolutions of about 60 centimeters, operating in an orbit similar to that of IGS 5A. The first satellite in the third generation of SAR spacecraft was launched in December 2011 and operates from a 510-Kilometer orbit.

The previous IGS launch occurred in January 2013 when an H-IIA202 rocket delivered IGS 8A and 8B into an orbit of 513 Kilometers. The 8A satellite is a 3rd generation SAR spacecraft and 8B a 5th generation optical satellite that returns imagery at resolutions of under 50 centimeters The. 8A satellite remains in its 513-Kilometer orbit while 8B has entered a lower orbit at an altitude of 427 Kilometers.

Because the IGS Satellites are military intelligence spacecraft, details on their design and operation are not provided. IGS spacecraft are built by Mitsubishi Electric, likely based on a commercial satellite bus.

It is known that the spacecraft have a mass of about 1,000 to 1,400 Kilograms when launched in pairs and that power generation is accomplished by solar arrays. Satellites launched without a companion could be much heavier based on the payload capability of the H-IIA which can deliver up to four metric tons into an IGS-type orbit. Orbital data of IGS spacecraft is not provided regularly, but satellite trackers around the world have been keeping tabs on the constellation.

The IGS satellite launching in January 2015 is a Radar Satellite launched as an in-orbit spare likely belonging to the third generation of SAR satellites to be ready to take over from IGS 7 launched in December 2011, passing the three-year mark in its mission which may be the identified design life of the spacecraft based on the behavior of IGS 1 & 4 satellites. It will be followed by another IGS later in 2015 which will be an operational 5th generation optical satellite following the experimental 5th generation satellite launched in 2013.

IGS Launch atop H-IIA delayed by bad Weather

January 29, 2015, Updated

Photo: MHI

The launch of a Japanese IGS Radar Reconnaissance Satellite atop an H-IIA rocket was delayed from Thursday due to unfavorable weather conditions at the Tanegashima Space Center. A new launch target of February 1 has been selected when persistent rain and thick clouds will have cleared out to permit the launch. Countdown operations were initiated as planned and final close outs of the launcher were conducted before H-IIA emerged from its Vehicle Assembly Building just after 12 UTC on Wednesday. Arriving at the second launch pad at the picturesque launch site on the southern tip of Japan, H-IIA started preparations for liftoff as teams began the usual procedures of connecting propellant, electrical and other commodity lines to the Mobile Launch Platform, working towards a planned T-0 time of 1:21 UTC on Thursday, the opening of a 13-minute launch window. Throughout the day and night on Wednesday, the launch weather forecast worsened as thick clouds and rain moved into the area, making violations of launch weather criteria a certain possibility.

With persistent rain and only slim chances of good conditions during the launch window, teams decided to back out of the countdown prior to loading the rocket with propellants.

A new launch date of February 1 was announced by JAXA because this weather pattern is expected to linger for a few days, making a launch attempt impossible on Friday. Conditions for Friday are expected to be worse with improvement beginning on Saturday into Sunday. H-IIA has been rolled back to the Vehicle Assembly Building where it will wait for its next launch attempt. Sunday's launch window stretches from 1:21 to 1:34 UTC.

Due to the classified nature of the IGS program, updates on the launch and any information on the satellite are not available to the public. There will be no official launch broadcast and the only information that will be provided is a confirmation of launch success.

January 28, 2015

A Japanese
H-IIA rocket is ready for the launch of a semi-classified radar reconnaissance
satellite on Thursday to keep Japan’s fleet of optical and radar surveillance
satellites topped up and in operation. Liftoff of the H-IIA is set for 1:21 UTC
on Thursday, the opening of a 13-minute launch window. The mission is of a
semi-secret nature – there will be no official launch broadcast and the only
information that will be provided is a confirmation of launch success.
The
satellite to be launched on Thursday is part of Japan’s IGS satellite
constellation (Information Gathering Satellites) that have gone through several
generations of optical and radar imaging spacecraft since the program’s first
launch in 2003. Over the course of the program, more and more advanced
satellites were launched achieving better ground resolutions for optical and
radar data products. The satellites also operate from different orbits.
The IGS satellite launching in
January is a Radar Satellite launched as an in-orbit spare likely
belonging to the third generation of SAR satellites to be ready to take over
from IGS 7 launched in December 2011, passing the three-year mark in its
mission which may be the identified design life of the spacecraft based on the
behavior of earlier IGS satellites. It will be followed by another IGS later
in 2015 which will be an operational 5th generation optical satellite following
the experimental 5th generation satellite launched in 2013.
JAXA issued
the confirmation of the planned launch date and window on Tuesday and
officially identified the satellite as IGS Radar Spare. Mitsubishi Heavy
Industries, operator of the H-II rocket fleet, will not issue any updates on
the launch and the only official information will confirm the liftoff and the
separation of the satellite into the target orbit less than 25 minutes after
launch. No information on pre-launch processing milestones for this mission are
available and there will be no official launch webcast. Usually, there will be
amateur webcasts and photos from the visitors site covering the initial stages of the
H-IIA flight.

*File Image* - Credit: JAXA

Countdown operations are expected to begin with the rollout of the H-IIA rocket from the Vehicle Assembly Building to the second launch pad at the Tanegashima Space Center, planned to begin at 12 UTC on Wednesday. Riding atop the Mobile Launch Table, the H-IIA rocket will take about 30 minutes for the 400-meter trip – being centered in a precise position at the launch pad. After arriving at the Pad, technicians connect data and electrical lines and put propellant umbilicals in place before completing final fueling preparations and close-outs. About eight hours before launch, teams evacuate the launch pad to get ready for the long propellant loading sequence.

Beginning at about X-7 Hours and 45 Minutes, the complex propellant loading sequence gets underway with the pressurization and chilldown of ground support systems handling the -183-degree Celsius LOX and -253°C LH2. Fueling goes through a number of steps including ground support system chilldown, propellant tank chilldown and propellant loading, before tanking enters replenish mode. The propellant loading sequence takes approximately three hours until the 116,600 Kilograms of cryogenics needed for launch are loaded. Replenishing the propellants as they boil off, the tanks are kept at topping level until late in the countdown

*File Image* - Photo: JAXA

The majority of the countdown will be spent with extensive tests of the launch vehicle's flight control system, checks of all electronics and controllers and verifications of the radio link between the launcher and the ground. Flight Termination System testing is also performed in the early stages of the countdown. H-IIA 202 has a liftoff weight of 285,000 Kilograms standing 53 meters tall with a core diameter of 4 meters using a two-stage stack with two Solid Rocket Boosters attached to the first stage. The rocket is capable of delivering payloads of up to 4,500 Kilograms to an IGS-type Sun-Synchronous Orbit.

The first stage of the H-IIA is 37.2 meters long and capable of holding about 100,000 Kilograms of cryogenic propellants, Liquid Oxygen and Liquid Hydrogen for consumption by the single LE-7A main engine. LE-7A is a staged combustion cycle engine delivering 1,087 Kilonewtons of thrust. Attached to the first stage are two SRB-A Solid Rocket Boosters - each 15.1 meters long and 2.5 meters in diameter weighing 76.4 metric tons.

Each of the boosters (when flying in the SRB-A configuration) burns around 65,000kg of propellants during a 110-second burn. SRB-A delivers 2,260kN of thrust. Booster separation is triggered by pyrotechnics and the SRBs use struts to ensure a clean separation.

The second stage of the H-IIA 202 is 9.2 meters long with a diameter of 4 meters. It also uses LOX and LH2 propellants, being filled with 16,600kg of cryogenics. One LE-5B engine powers the second stage providing a vacuum thrust of 137kN. The engine can make multiple ignitions to target a variety of orbits.

At X-60 Minutes, the Terminal Countdown Sequence will start. During the final hour of the countdown, last-minute items will be closed out and the vehicle will be reconfigured for the Automatic Countdown Sequence starting just 4.5 minutes prior to blastoff

As computers are given control of the countdown, H-IIA's Propellant Tanks will be pressurized for flight. At X-3 minutes, the launch vehicle is switched to internal power while ‘IGS Radar Spare’ will have been switched to battery power ahead of the final countdown sequence. One minute before liftoff, thousands of Kilograms of water are being poured over the launch platform to suppress the acoustic loads at ignition & liftoff. Launch Vehicle Ordnances will be armed at X-30 Seconds and the Guidance System of the Vehicle is being switched to Flight Mode 12 Seconds later before the sparklers underneath the LE-7A main engine ignite to burn off residual Hydrogen.

Ignition Sequence Start is commanded at X-5.2 Seconds and the LE-7A Engine soars to life as the turbopumps spin up to flight speed being monitored by on-board computers to make sure the engine is healthy before the booster ignition command is issued at T-0 - committing the vehicle to launch. At the moment of booster ignition, the H-IIA rocket leaps off its pad with a total thrust of around 570 metric ton-force with the two boosters delivering 75% of the total thrust at liftoff, supplying the extra kick needed to send IGS on its way. H-IIA will make a short vertical ascent before beginning to pitch and roll in order to get aligned with its precisely planned ascent path taking the launch vehicle to the south-east for a Dogleg Maneuver. On its way uphill, H-IIA quickly passes Mach 1 and Maximum Dynamic Pressure.

To reach a polar orbit from its picturesque launch site located on the southern tip of Japan, H-IIA will have to make a Dogleg Maneuver. A Dogleg is a powered turn in the ascent trajectory of a rocket. For a direct ascent into a polar orbit, H-IIA would need to fly south-west over the Philippines. To avoid populated islands located along the direct ascent path, the Dogleg has to be inserted in order to ensure no launch vehicle debris hit populated areas, both during a nominal flight and in a launch failure.

For the Dogleg, H-IIA will fly downrange for about 100 Kilometers sticking to a south-easterly path before initiating the turn to the south-west late in the first stage burn, ensuring that all debris fall short of populated areas. A Dogleg comes at the cost of launch vehicle performance in terms of payload capability as additional fuel is required for the turn. The two boosters burn for about 100 (SRB-A) to 115 (SRB-A3) seconds - burnout will be sensed by the declining pressure in the combustion cambers. Booster jettison occurs after thrust tail-off as both SRBs separate simultaneously after completing their job of helping accelerate the vehicle to ~1.5 Kilometers per second. Powered flight continues on the LE-7A engine of the first stage alone. The engine delivers 109,300 Kilograms of thrust, burning about 260 Kilograms of cryogenics per second.

Image: JAXA/Spaceflight101

Typical Dogleg Trajectory from Tanegashima

Passing T+4 minutes, H-IIA will reach an altitude of over 130 Kilometers making it safe to jettison the Payload Fairing as aerodynamic forces can no longer harm the spacecraft. Separating the fairing as early as possible increases ascent performance as additional weight is lost at fairing separation.

In a nominal flight scenario, H-IIA’s first stage will burn until T+6 minutes and 36 seconds, accelerating the launch vehicle to over 5.0 Kilometers per second. Stage separation occurs eight seconds after cutoff as pyrotechnics cut the connection between stages and springs push the Core Stage away. The LE-5B engine of the second stage will ignite six seconds after stage separation, delivering 13,970kgf of thrust over a burn of up to 8.5 minutes to deliver the IGS satellite to its target orbit with spacecraft separation occurring prior to T+20 minutes. The target orbit will be circular, around 500 Kilometers in altitude at an inclination of 98 degrees.

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